The invention includes methods for reducing or preventing the staining capacity of a compound to a tooth in a mammalian oral cavity, which includes affixing to the tooth surface a degradable film. The film comprises a starch polymer or copolymer that is formed by crosslinking a starch. The film degrades in the oral cavity within about 1 minute to about 70 minutes after affixation. In some embodiments, it may be preferred the crosslinking occurs in the presence of at least one (poly)carboxylic acid. It may be preferred that the starch selected is a retrograde starch, a starch that is chemically or physically modified to be amylase resistant or a starch that is derived naturally but exhibits amylase resistance.
